This invention related to multi-line telephone communications systems having one or more telephone units of which each provides access to several telephone lines and visibly indicates the status of each such line.
Multiple-line key telephones, sometimes referred to as "trading telephone", are widely used in rapid communications networks such as trading operations in banks, brokerage houses and other financial institutions. Telephones of this type provide direct access to several outside lines with the simple depression of a single key on the telephone. Dialing is unnecessary. Each telephone unit, also referred to as a telephone station, may be capable of selecting any of several-handed different lines, and should at the same time provide all normal telephone functions, i.e., dialing, ringing, hold, etc. One essential requirement is that each telephone station furnish an indication of the present status of each of the lines accessible at the particular station. This indication usually takes the form of a continuously lighted key for a "busy" line, a flashing key for a line on "hold" or for a "ring" on an incoming call, and a non-lighted key for a free line. In addition, the station should have the capability of indicating which line the user has picked up.
By combining the push button with the display, more information could be offered to the user visually.
The user is able to know the name of the caller of the incoming line on hold by the figures on the display.
A trading system having display is indicated in U.S. Pat. No. 4,998,275, U.S. Pat. No. 5,046,086, U.S. Pat. No. Des. 313,601, U.S. Pat. No. Des. 313,602, U.S. Pat. No. Des. 313,600, and U.S. Pat. No. Des. 325,738.